Ratchet-drill attachment.



A. f. DBRRICK L R. W. GARRISUN.

RATGHET DRILL ATTACHMENT. APPLIOATION FILED FEB. s, 1909.

Patented Dec. 28, 1909.

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abbina# UNITED STATES PATENT OFFICE.

ALBERT F. DERRICK AND RICHARD W. GARRISON, OF OAKLAND, CALIFORNIA.

RATCI-IET-DRILL ATTACHMENT.

Application filed February 3, 1909.

To all whom it may concern:

Be it known that we, ALBERT F. DERRICK and RICHARD WV. Garrison,citizens of the United States, residing at Oakland, in the county ofAlameda and State of California, have invented new and usefulImprovements in Ratchet-Drill Attachments, of which the following is aspecification.

This invention relates to ratchet drills and more particularly to anattachment therefor in the nature of a device for automatically feedingthe drill and regulating the drilling` pressure so as to obviate thedanger of the drill snapping under undue power.

The invention has for one of its objects to improve and simplify theconstruction and operation of devices of this character so as to becomparatively simple and inexpensive to manufacture, reliable andefficient in use, and so .designed as to be readily applied to anordinary ratchet drill.

Another object of the invention is the provision of a device of thecharacter referred to including a yieldingly mounted feed screw which,under ordinary conditions, is prevented from turning so that a "step bystep movement of the ratchet drill will feed the latter continuously,the screw being yieldingly mounted to permit the same to turn with theratchet drill when the pressure on the drill point becomes excessiveowing to too rapid feed or excessive hardness of the metal being drilledwhen the metal varies in density.

With these objects in view and others, as will appear as the descriptionproceeds, the invention comprises the various novel features ofconstruction and arrangement of parts which will be more fully describedhereinafter and set forth with particularityA in the claims appendedhereto.

In the accompanying drawing, which illustrates one embodiment of theinvention, Figure 1 is a side view of the attachment. Fig. 2 is alongitudinal section thereof. Fig. 8 is a side view showing theattachment applied to a drill in operative position. Fig. 4 is a detailview showing the inner or head end of the feed screw and the bearingplate therefor. Fig. 5 is a plan view of the device. Fig. 6 is a planview of the collar or sleeve in which the head is mounted.

Similar reference characters are employed to designate correspondingparts throughout the views.

Referring to the drawing, and more par- Specification of Letters Patent.

Patented Dec. 2S, 1909. Serial No. 475,876.

ticularly to Fig. 1, A designates an ordinary ratchet drill providedwitha tool or twist drill 1, and attached to the ratchet drill is the feeddevice and pressure regulator B which, togetherwith the drill, issupported in an ordinary brace or old man (l whereby the drill ismaintained in operative relation to the work 2.

The attachment B consists of a barrel or cylinder 3 internally threadedat both ends and in the lower end thereof is screwed a sleeve 4 whichhas parallel faces 5 at opposite points for accommodating the wrench inorder to screw or unscrew the sleeve. This sleeve has a smooth bore 6 inwhich is slidably disposed the smooth cylindrical shank 7 of the feedscrew 8, which latter projects below the sleeve and is threaded in thebody 9 on the ratchet drill so that the step by step movement of suchbody will feed the ratchet drill for boring the work. The inner end ofthe screw has a fiat or diskshaped head 10 which bears on the inner faceof the sleeve 4, which inner face has oppositely-disposed recesses 11,as shown in Fig. 6, for receiving radial lugs 12 on the under face ofthe head 10 that serve as a key for preventing relative turning of thescrew under normal conditions of operation. The screw is maintained indepressed position with the lugs 12 engaging in the slots 11 by ahelical compression spring 13 disposed within the barrel or cylinder 3,and the lower end of this spring rests upon a plate 14 loosely mountedin the cylinder and against which the upper surface of the head bears.This upper surface of the head is conical, as shown in Fig. 4, to engagein a slightly hollow conical bearing 15 in the bottom face of the plate14. In the upper end of the cylinder is threaded a cap 16 that has acentral threaded opening 17 for receiving the spring tensioning screw18, and on the upper end of the screw is a squared point 19 which entersan opening in the upper arm of the brace C and serves to prevent theattachment from turning. The inner end of the screw bears on a plate 2Oon which the upper end of the spring abuts, and by adjusting the screwinwardly, the tension of the spring can be increased. This adjustingscrew 18 is clamped in set position by a jam nut 21 engaging the threadsthereof and co- (fiperating with the cap 19 to hold the screw ast.

In operation, the ratchet drill and attachment are set up in the brace Cin the manner shown in Fig. 3 and the drill is manipulated by the backand forth movement of the handle 22 of the ratchet drill so that a stepby step rotary movement is imparted to the twist drill. By the movementof the ratchet drill in this manner, the relatively stationary screw 8advances the ratchet drill for boring the work. Should the drill fail toadvance in proportion to the pitch of the screw 8, the latter willgradually yield inwardly against the tension of the spring l?, and, ifthe pressure becomes excessive owing, for instance to a harder or denserportion of the metal being encountered by the drill, the screw will moveinwardly to such an extent as to disengage the lugs l2 from the slotsl1, thereby relieving the pressure from the twist drill while at thesame time allowing the feed of the drill to be accommodated to thenature of the metal.

From the foregoing description, taken in connection with theaccompanying drawing, the advantages of the construction and of themethod of operation will be readily apparent to those skilled in the artto which the invention appertains, and-while we have described theprinciple of operation of the invention, together with the devicewhichwe now consider to be the best embodiment thereof, we desire tohave it understood that the device shown is merely illustrative, andthat such changes may be made when dei sired as are within the scope ofthe claims appended hereto.

Having thus described the invention, what we claim is 1. A device of theclass described comprising a chambered body having a smooth opening inone end thereof, a screw having a smooth portion slidably mounted in theopening, a head on the inner end of the screw, interlocking meansbetween the head and body, a spring within the body and pressing on thehead for normally maintaining the said means in interlocking relationand permitting the screw to move inwardly to disengage the saidinterlocking means, and means on the ends of the body opposite from thescrew for holding the device in operative relation with a supportingbrace.

2. A device of the class described comprising a barrel, a sleeveremovably secured to one end of the barrel and provided with a smoothbore, a feed screw having a smooth shank slidably mounted in the bore, ahead on the inner end of the screw having its under face presented tothe inner face of the sleeve, a slot in one of the faces, a lug on theother face engaging in the slot for preventing relative turning of thesleeve and screw under normal conditions, a spring in the barrelconstantly pressing on the head to maintain the lug engaged in the slot,and means for adjusting the tension of the spring supported on the endof the body opposite from the screw and for holding the device inoperative position.

3. A device of the class described comprising a barrel, a sleeveremovably secured to one end of the barrel and provided with a smoothbore, a feed screw having a smooth shank slidably mounted in the bore, ahead in the inner end of the screw having its under face presented tothe inner face of the sleeve, a slot in one of the faces, a lug on theother'face engaging in the slot for preventing relative turning of thesleeve and screw under normal conditions, a spring in the barrelconstantly pressing on the head to maintain the lug engaged in the slot,a screw in the end of the body opposite from the first-mentioned screwand arranged to vary the tension of the spring, and a point on the endof the screw of non-circular crosssection.

t. A device of the class described comprising a barrel having aliningopenings at opposite ends, one opening being smooth and the otherthreaded, a feed screw having a smooth shank slidably mounted in thesmooth opening, a screw threaded in the other opening, a spring in thebarrel, plates between the innerI ends of the screw and spring,interlocking means between the barrel and feed screw for preventingrelative turning while the spring is fully extended. said interlockingmeans being automatically released by inward pressure on the feed screw,means for clamping the second screw in fixed relation to the barrel, anda noncircular pointed tip on the outer end of the.

second screw.

In testimony whereof we affix our signatures in presence of twowitnesses.

ALBERT F. DERRICK. RICHARD lV. GARRISON. lVitnesses z JOHN ALDRIDGE,CHARLES ScRivEN.

